Thank you all for the help over the last week or so, my SB6r is now up and running , not 100% as the carbs want balancing but at least I can use it. A post by Lorenzo said cut a piece of cloth ( t shirt ) same size as the air filter foam and place it between the foam and top of the air filter box . I don't know how or why but it's got me on the road again, so for now I will use it and try and figure it out over the winter. Once again thank you all. Cheers Nigel_________________Horseheed

To my thinking... the piece of cloth will reduce the amount of airflow into the engine, which will in turn make the mixture more rich. So, if my thinking is correct, you need to add more fuel to the circuit in the rev range that is struggling.